For operation performance of an automobile, it is very important to achieve higher rigidity of a body and improvement in aerodynamic characteristics while the center of gravity of the automobile is located in a lower position. Such a demand is strong particularly in a sports car. Conventionally, in a front engine rear drive vehicle, what is called a tunnel structure extending from front to rear of the vehicle for the purpose of allowing passage of a propeller shaft is adopted in a front panel. Moreover, in order to suppress lowering in the rigidity of the body due to adoption of the tunnel structure, a reinforcing member is additionally provided. There is a limit, however, to further higher rigidity of the body because of restriction on layout of a driveline and an exhaust pipe.
The vehicle desirably has a completely flat bottom face, in order to improve its aerodynamic characteristics. On the other hand, if a structure in which the exhaust pipe is completely covered is adopted, it is necessary to position the entire powertrain higher from the ground, from a viewpoint of ensuring ground clearance. In particular, if an engine with a heavy mass is positioned higher, the center of gravity of the vehicle is also higher.
Meanwhile, it is effective to dispose the engine with a heavy mass in further lower portion of the vehicle, in order to achieve lower center of gravity of the vehicle for the purpose of improving the operation performance of the vehicle. In order to dispose the engine in a further lower portion of the vehicle, however, the entire powertrain should also be lowered. In such a case, apparatuses constituting the powertrain may interfere with the exhaust pipe or an undercover provided on the bottom face of the vehicle. In addition, as a lowermost area of the entire powertrain is further lowered, the ground clearance is not ensured.
Japanese Patent Laying-Open No. 03-235721 discloses a powertrain for use in a 4WD vehicle based on FR (front engine rear wheel drive), in which a crankshaft of an engine, a propeller shaft, and an input shaft of a transmission are coaxially provided. In addition, in the powertrain structured as above, generally, an exhaust pipe and an undercover are disposed below the powertrain.